I know some members have posted that it is a 'successful' reseeder but that hasn't been my experience.

Just like you I love this plant; maybe my favourite perennial in the month of September.

Over the year, I've maybe had a handful of seedlings. One was quite nice, with a paler yellow flower than the parent.

Something I've run into with other plants is no seedlings until I introduce another cultivar of the same species.

I have 3 nice clumps of LQ, let its stalks stay over winter for the last 2 years and never had seedlings.

I found one plant which looked like a reverted version, brown center and yellow petals, but that had just 3 stalks very near to the original, so I rather thought it was some kind of mutation- not a seedling. It was just as tall as the pale yellow flowering stalks, so I labeled it and removed it in fall.

My Helianthus LQ does reseed lightly. Only a few seedlings, which resemble the parent closely, but nothing out of hand. However it IS a rampant spreader for me, and it runs roughshod over the other perennials and grasses nearby.

3 years ago the voles did a number on the patch. They probably ate 90% of it, along with the Baptisia, some Hostas, Eupatorium, etc. That was one instance where I was kind of glad that the voles had eaten them back. 2 years later you wouldn't even know the voles had touched them, whereas it is taking the other perennials much longer to rebound from extensive vole damage.